Development of Specific Modes of Motivational Equilibration

The appearance of definite patterns of response, which look immediately or eventually to the removal of a particular motivational irritant, is due to the processes of individual learning.

If we are to understand how the activity occasioned by basic tissue conditions becomes organized along definite lines and associated with new and more elaborate patterns of afferent excitation, we must reconstruct what occurs in the life span of the individual, particularly in his early years. Reports obtained by the relatively crude methods of natural observation and case history lead to two important principles, neither of which can yet be satisfactorily placed in a definite physiological context. (I) In random activity aroused by some internal excitant, those acts will be fixated and made dominant which lead with the greatest dispatch to an equilibration of the internal disturbances. (2) The external stimuli which connect with this activity come to have increasing potency in arousing that activity. As some part of the generalized behavior first excited by internal organic stimuli is fixed, it shows a tendency to become somewhat divorced from its original excitant, and to become attached instead to the external stimuli representing the object which satisfies the tissue need. Often this transfer is so marked that the external stimuli can arouse the fixated responses without summational aid from the motivational excitants. It is common knowledge that a human infant will not take food except when hungry. The grasping and sucking responses, which are the fixated remnants of undifferentiated random activity, cannot be elicited if the stomach is loaded with food.

Yet a few years later this same individual will eat a favorite food even when he confesses to being already satiated. The same thing can be said for all the other motivational excitants. Responses of wellbeing, originally due to the relaxation following removal of an irritating internal condition, become associated with the object (mother) which has produced the release. The inhibitions placed upon the performance of sexual acts in the presence of appropriate sex objects undoubtedly enhances their stimulating value, so that later on they may arouse the response with little aid from an internal excitant.

While this inventory could be continued, it would not further the soluton of the physiological problem. The basic question to be answered is: How is it possible for a pattern of persistent afferent excitation from certain interoceptors, acting in conjunction with a variable pattern of excitation from exteroceptors, able to fashion, out of activity originally random, a particular mode of response which meets the internal need? We have touched on this problem many times. Now let us consider three theories which have been proposed to account for it.